Alzheimer's treatments consist mainly of medications that stabilize cognitive function, if only for a short period of time. These drugs stage a holding action, primarily postponing further cognitive declines.

But the Alzheimer's treatments of the future will focus more on preventing the disease, which can begin decades before a person experiences its signs and symptoms. Increasingly, even as investigators work to detect Alzheimer's at its earliest stage, they're also looking to arrest its progress when the effects may still be reversible.

Early studies in mice showed that immunization with amyloid-beta peptide reduced the number of plaques — clusters of abnormal cells associated with Alzheimer's disease — in the brain. But a trial of an Alzheimer's vaccine in humans was halted after some participants developed brain inflammation.

Scientists continue to search for an Alzheimer's vaccine that will not produce such dangerous side effects.

Medications called secretase inhibitors interrupt the actions of enzymes that lead to plaques in the brain. To be safe, though, these drugs must be able to target only the harmful actions of secretase and not interfere with the enzymes' normal functions in the body.

Another major challenge is that a secretase-inhibiting drug must be able to cross the blood-brain barrier that surrounds and protects the brain from foreign substances in the blood. This barrier typically doesn't allow large molecules to pass into the brain.

Some studies have shown that taking statins — cholesterol-lowering drugs — in midlife reduces a person's risk of dementia. Other studies, however, have failed to find this association. If there is a link between high cholesterol and Alzheimer's, the risk of Alzheimer's could be reduced by controlling cholesterol levels through diet and medication.

Along similar lines, a large study found that people who took medications to lower blood pressure had a reduced risk of vascular dementia, which is caused by a series of small strokes. Because vascular dementia and Alzheimer's appear to be linked, controlling high blood pressure may also help prevent Alzheimer's.

Inflammation appears to play a role in Alzheimer's, although it's still unknown if it's a cause or an effect of the disease.

Several studies indicate that anti-inflammatory drugs, such as ibuprofen (Advil, Motrin, others), naproxen sodium (Aleve) and indomethacin (Indocin), may reduce the risk of developing Alzheimer's disease. But these types of drugs can also cause serious gastrointestinal bleeding, so more studies are needed to determine whether the benefits outweigh the risks.

Early studies indicated that hormone replacement therapy, typically prescribed to ease menopausal symptoms, might protect women over the age of 65 against Alzheimer's. But more recent studies not only refute these findings, but also suggest that this hormone therapy might even increase the risk of dementia.

The timing of the hormone replacement therapy may be the reason for apparently contradictory results. Some researchers speculate that early hormone therapy, during a woman's 50s, may be protective, while later use becomes harmful.

Medications that mimic estrogen's effects, such as the osteoporosis drug raloxifene (Evista), may provide cognitive benefits without estrogen's risks.

In men, low testosterone levels have been linked to increased risk of Alzheimer's disease. Researchers are investigating whether testosterone supplements might help men who have Alzheimer's or are at risk of the disease, but the results have been mixed.

New Alzheimer's treatments take time to develop, and then even more studies are needed to establish a treatment's safety and effectiveness. But all this time and effort will eventually pay off. Most researchers expect to see major progress in the treatment and prevention of Alzheimer's in the next few decades.